Transpedicular Corpectomy and Fusion for Metastatic Tumor or Infection

30 Transpedicular Corpectomy and Fusion for Metastatic Tumor or Infection

Young M. Lee, Ramin A. Morshed, and Dean Chou

Summary

Tumors and infections of the spine are often indications for the use of transpedicular corpectomy and fusion. The use of open transpedicular corpectomies for these indications is a well-developed technique. In this chapter, we review the technique of minimally invasive transpedicular corpectomy along with patient selection, preoperative planning, postoperative care, and complication avoidance.

Keywords: transpedicular corpectomy minimally invasive surgery trap door osteotomy rib head osteotomy tumor

30.1 Introduction

The use of transpedicular corpectomy allows for an anterior surgery to be performed, but from a posterior approach. Common indications for the use of transpedicular corpectomy include stabilization, neurologic function preservation, pain relief, and resection of tumor or removal of infectious nidus. The use of open transpedicular corpectomies is a well-developed technique,1^,²^,³^,⁴ but one important variation includes the minimally invasive technique.

30.2 Patient Selection: Indications and Contraindications

Typical indications for transpedicular corpectomy typically include a lesion (tumor or infection nidus) that is anterior to the spinal canal. However, trauma and the need for stabilization/pain relief can be another indication for transpedicular corpectomy. The use of the minimally invasive transpedicular corpectomy has a particular advantage which is true for patients at high risk of morbidity/mortality from a larger operation, such as the obese or the elderly. A relative contraindication to the minimally invasive transpedicular approach is in the case of complex revision cases, during which extensive scarring and destruction of normal anatomy may make surgery difficult.

30.3 Preoperative Planning

Preoperative planning should include review of magnetic resonance imaging (MRI) and computed tomography (CT) scans to evaluate the location of infection and/or tumor. Routine presurgical laboratory tests, including chemistry, complete blood cell count, and coagulation panel with type and screening for blood products should be performed. Neuromonitoring should be available and the procedure is typically performed under somatosensory evoked potential (SSEP), motor evoked potential (MEP), and electromyography (EMG) monitoring. Anesthesiology teams should be made aware that neuromonitoring will be performed so that paralytic agents can be avoided during the critical portions of the case when neuromonitoring is required. The fluoroscopic C-arm should be made available as it is critical in the localization of the correct level and the placement of percutaneous pedicle screws.

30.4 Patient Positioning

After induction with general anesthesia, a urinary catheter is inserted, neuromonitoring equipment is set up, and then the patient is positioned prone. This is typically done on a Jackson table to minimize abdominal compression and associated venous hypertension. For thoracic levels, a Wilson frame may be more suited to the natural kyphosis at these levels. The head can be position in a padded head frame or horseshoe but care must be taken to avoid excess orbital pressure. Some authors advocate for Mayfield fixation to avoid this.⁵ Anesthesiologist must also have access to manage airway issues, so a neutral neck position is ideal. The arms are positioned forward at right angles with elbows in-line with the shoulders. Padded chest and hip rests in addition to knee and ankle padding prevent pressure sores from developing during long operative times. Fluoroscopy is set up in the room, and the desired level is localized using a C-arm and marked externally.

This is a hybrid minimally invasive surgery (MIS) approach that, if done technically well, can significantly reduce blood loss, tissue disruption, and infection rates from metastatic tumor resection. Three-dimensional navigation can be extremely helpful—also for the corpectomy portion—to identify the healthy end plates above and below and confirm good bilateral and anterior decompression, as well as for screw placement. Preoperative embolization may be helpful. If significant blood loss is encountered it may be safer to place bone cement instead of a structural cage.

30.5 Surgical Technique with Illustration/Example

30.5.1 Step 1: Incision

After preoperative fluoroscopy is utilized to localize the correct level, a midline skin incision is performed with preservation of the fascia (Fig. 30.1 and Video 30.1).

Fig. 30.1 (a) The skin incision is planned based on the radiographs. (b) The skin incision is made while preserving the fascia and retraction is performed (c) and (d) K-wires are inserted under fluoroscopic guidance.

Video 30.1 Mini-open transpedicular corpectomy.

30.5.2 Step 2: Pedicle Screw Insertion

Percutaneous pedicle screws are placed two levels above and below the planned corpectomy site using Jamshidi needles, Kirschner wires, and cannulated screw system under fluoroscopic guidance (Fig. 30.2).

Fig. 30.2 (a) After the pedicle is tapped and the K-wire is inserted, cannulated screws are inserted. (b) The cannulated screws are inserted two levels above and below the planned corpectomy site. (c) A midline fascial opening is performed and (d) a retractor is placed.

30.5.3 Step 3: MIS Ipsilateral Transpedicular Corpectomy

A midline fascial opening is performed over the corpectomy level and partial exposure of the lamina above and below is performed. At this point, an expandable tubular retractor or a standard cerebellar retractor can be placed (Fig. 30.3).